The following information is provided to assist the reader in understanding technologies disclosed below and the environment in which such technologies may typically be used. The terms used herein are not intended to be limited to any particular narrow interpretation unless clearly stated otherwise in this document. References set forth herein may facilitate understanding of the technologies or the background thereof. The disclosure of all references cited herein are incorporated by reference.
Poor water solubility is one of the major hurdles for the advancement of drug candidates into clinical applications. Most drug companies focus on orally deliverable drugs. Not all drugs are orally bioavailable, however. Bioavailability may, for example, be defined as the fraction of an administered dose of unchanged drug that reaches, for example, the systemic circulation. Some compounds/drugs may be degraded in the digest tract, while some may be too harmful for the epithelial lining. In many cases, the duration of the free drug in blood once absorbed is very short. Any one or combination of these problems for a drug candidate may result in the elimination or cessation of drug development (as a general practice in the pharmaceutical industry).
The current drug discovery process is costly and inefficient. Many promising drug candidates have failed to reach the market primarily as a result of poor water solubility, low bioavailability and toxicity issues. Formulation development thus represents an important strategy to maximize the success of drug discovery. In addition, formulations can improve the therapeutic index of existing drugs. Among various types of delivery systems studied, polymeric micelles have gained considerable attention due to their simplicity, small sizes (10-100 nm), and the ability to solubilize water-insoluble drugs and accumulate specifically at the tumors. Most of the carrier materials in polymeric drug delivery systems (including lipid-core micellar systems) utilize “inert” excipients that lack therapeutic effect. The use of excess amounts of carrier materials may, for example, add to cost and potentially impose safety issues.